Stroke Alert: A Review of Current Clinical Stroke Literature

By Matthew E. Fink, MD, Interim Chair and Neurologist-in-Chief, Director, Division of Stroke & Critical Care Neurology, Weill Cornell Medical College and New York Presbyterian Hospital

Tsivgoulis G, et al. Multicenter external validation of the ABCD2 score in triaging TIA patients. Neurology 2010; 74: 1351-1357.

Rapid identification and diagnosis of patients with TIA is important to prevent subsequent stroke, which occurs in about 10% of all TIA patients in the 90 days following TIA. Half of those strokes occur in the first week following the TIA. The ABCD2 score was developed as a way to stratify patients, based on risk factors, in order to identify which patients should be hospitalized and intensively investigated and monitored. The score is calculated based on the following items: Age > 60 years = 1 point; Blood pressure (systolic > 140 or diastolic > 90 = 1 point); Clinical features (unilateral weakness = 2, speech disturbance without weakness = 1, other symptoms = 0; Duration of symptoms ( < 10 mins = 0, 10-59 mins = 1, > 60 mins = 2); Diabetes mellitus (yes = 1).

The authors studied 148 patients who presented with TIA, applied the ABCD2 score, and followed them for subsequent stroke. The seven-day and 90-day risks of stroke were 8% and 16%. The ABCD2 score accurately discriminated between TIA patients with a high seven-day or 90-day risk of stroke. The 90-day risk of stroke was 7-fold higher in patients with an ABCD2 score of > 3 points. After adjustment for other risk factors that were not part of the score, an ABCD2 score of > 2 was associated with a 5-fold greater 90-day risk of stroke (HR=4.65, 95%CI 1.04-20-84, p=0.045). The score was not able to identify patients who will have a stroke at seven days vs 90 days, requiring that all patients undergo rapid assessment for treatable conditions that might cause a stroke.

Lee M, et al. Efficacy of intra-arterial thrombolysis for acute ischemic stroke. Meta-analysis of randomized controlled trials. Stroke 2010;41: 932-937.

Intra-arterial thrombolysis (IA) for acute ischemic stroke is widely used throughout the world, but has not been approved by the U.S. Food and Drug Administration (FDA). It remains an important alternative to intravenous thrombolysis because of the improved recanalization of large artery occlusions, and an expanded time window (up to 6 hours). Because no single, randomized, clinical trial (RCT) has demonstrated statistically significant increases in good or excellent outcomes (modified Rankin scores 0-2) compared to the control groups, the authors performed a systematic literature review and meta-analysis of published RCTs that met strict criteria, and combined the results, with special emphasis on good or excellent outcomes.

Their search identified five RCTs with 395 patients comparing IA fibrinolysis with control. IA was associated with increased good outcomes (mRankin 0-2; OR=2.05, p=0.001) and excellent outcomes (mRankin 0-1; OR=2.14, p=0.003). In addition, there was significant improvement in the NIHSS and the Barthel index in the IA fibrinolysis groups compared to control. Although there was an increased rate of intracerebral hemorrhage in the IA group, this was not associated with an increase in mortality.

Chernyshev OY, et al. Safety of tPA in stroke mimics and neuroimaging-negative cerebral ischemia. Neurology 2010;74:1340-1345.

Rapid and widespread use of intravenous tpa for treatment of acute ischemic stroke is hampered by fear on the part of emergency department staff of giving the drug to a patient misdiagnosed with ischemic stroke, who ends up with another diagnosis (stroke mimics). The authors addressed this issue by reviewing their stroke registry from 2004–2008 and identifying all patients treated with IV tPA who subsequently had negative imaging.

Among 512 treated patients, 21% were found to not have an infarct on follow-up imaging. In the "stroke mimics" group (14%), average age was 55 years, median NIHSS was 7, and discharge NIHSS was 0, and there were no instances of symptomatic intracerebral hemorrhage. The most common final diagnoses were seizure, complicated migraine, and conversion disorder. In the group identified as "neuroimaging-negative cerebral ischemia" (7%), the average age was greater, but once again, there were no instances of symptomatic intracerebral hemorrhage and all patients had a normal examination at time of hospital discharge. The authors concluded that it is safe to administer tPA to patients who are later diagnosed as "stroke mimics" or TIA.

Schievink W, et al. Screening for intracranial aneurysms in patients with bicuspid aortic valve. Neurology 2010;74:1430-1433

Bicuspid aortic valve (BAV) is a common congenital heart defect that affects up to 2% of the population. A connective tissue disorder is suspected as a cause for this disorder, which may also involve the intracranial arteries, and the authors therefore screened a group of patients with BAV for the presence of intracranial aneurysms. In a group of 61 patients with BAV (mean age was 48 years, range 29-70), MRA or CTA were used to screen for aneurysms, and compared to an aged-matched control group of 291 people.

Intracranial aneurysms were found in 6 of 61 patients with BAV (9.8%;95% CI 2.4-17.3) and this was significantly higher than in the control group (3/291 or 1.1%, p=0.0012). Known risk factors for intracranial aneurysm development, female sex and advanced age, were more common in the control group. There were no significant differences detected in age, smoking, hypertension, alcohol use, or aortic diameter between the BAV patients with and without aneurysms. BAV patients appear to have a significantly higher rate of intracranial aneurysms and the diagnosis should be considered and pursued in appropriate patients.